Slide members are often coated with nitride coatings like CrN or TiN, however more and more also diamond like carbon (DLC) are applied. It is considered useful for coating slide members, as readily providing a smooth surface and excellent in frictional characteristics. For example, Patent Reference 1 discloses a technique of forming a DLC film of the type a-C:H on a metal substrate. Patent Reference 2 describes a modification of a-C:H coatings by incorporation of different metals. The coatings are termed as a-C:H:Me coatings. Patent Reference 3 has realized improved the heat resistance and increased hardness of a DLC film by defining the content of the hydrogen content in the film at a low level ca. 5 at %. Patent Reference 4 and Patent Reference 5 disclose a DLC film containing Si in the carbon film.
Patent Reference 6 shows the modification of optical properties of a-C:H coatings by incorporation of silicon or boron.
However, since the coatings mentioned in Patent References 1 to 6 are based on carbon with some alloying elements like hydrogen and/or metal, or silicon or boron, the improvement in the heat resistance thereof is limited: to ca. 350-400° C. in the phase stability and to ca. 400-500° C. concerning the oxidation in air.
Contrary to this, the applicant of the present invention has proposed an Si (BCNO)-based film as in Patent Reference 7, for enhancing the heat resistance thereof and further increasing the hardness thereof. Accordingly, the abrasion resistance and the heat resistance of the film for use for cutting tools and abrasion-resistant members have been drastically enhanced. Over Patent Reference 7, the present invention is to enhance not only the abrasion resistance and the heat resistance but also the sliding characteristics of the film.